#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int s = 0;
  for (int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    s += (b > a);
  }
  cout << s << endl;
  return 0;
}
